Results 1 to 4 of 4
  1. #1
    Join Date
    Sep 2010
    Location
    Philadelphia PA suburbs
    Posts
    7

    Lennox Discharge Air Sensor, Outdoor Air Sensor

    Lennox Communicating furnaces (SLP98, GV61/GV71) have options for connecting discharge air sensor(DAS) and outdoor air sensor(OAS). OAS can pass outdoor air temperature to icomfort thermostat.

    Do these have any value in controlling staging/variable speed ramp-up of furnace, A/C staging? Discharge sensor in particular seems easy to add if it were useful. Why is it not always used as part of the system if it helps or is it useful only in certain unusual circumstances ?

  2. #2
    Join Date
    Nov 2010
    Posts
    151
    I have the same question. Just started my new XC21 / SLP98V today, but I don't see the outside temp on the iComfort t-stat. I thought this outdoor sensor was built into the condenser just like the Trane communicating system? How come the outdoor temp is not showing up on the t-stat?

  3. #3
    Join Date
    Nov 2010
    Posts
    151
    Nevermind, the outdoor temp is showing in the weather tab. I was confused because the weather tab says that the weather features are not available on this system. Searching this forum I found the answer:

    "It's not there yet. The weather tab is reserved for "future development." As I understand it there will be an internet interface module that will wire into the furnace."

  4. #4
    Join Date
    Feb 2011
    Location
    Ontario
    Posts
    73
    I have the SLP98 and the XC21 with both the DAS and the OAS installed.

    The DAS allows the system to monitor the actual temperature of the SA and keep it even during heating. So you get move even heating with less temperature variation using the Fixed DAT (Discharge Air Temperature) than with the default Fixed CFM setting. You would need to try each in your particular installation to find out which is preferable.

    During cooling, the DAS allows you to check the DAT and make sure you are getting effective cooling, e.g., if your airflow is blocked by a dirty filter or coil, the DAT could drop lower and by using the iComfort installer settings diagnostics you could figure this out and correct the problem. During cooling, the system does not use the DAS to adjust airflow, during heating under the "Fixed DAT" setting it does.

    The OAS can be used to adjust the humidification setting automatically relative to the outdoor temperature (Dew Point Control) during the heating season. It can also provide a more accurate outdoor temperature reading as it can be located out of the sun. My installer first located the OAS inside the XC21 case and this produced readings way off the actual as the sun was heating the XC21 case. We moved it to a wall under some vines and readings were much more accurate. As well, with the OAS, the outdoor temperature appears on the iComfort Home screen.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event